Art of inlaying sheet material



P. F. sKooG ART OF INLAYING SHEET MATERIAL Nov. 16, 1948.

2 Sheets-Sheetl Filed April 28, 1945 mveu'ron PER F. SKOOG ATTORNEYSNov. 16, 1948. P. F. sKooG- ART OF INLAYING SHEET MATERIAL 2Sheets-Sheet 2 Filed April 28, 1945 lui Srmentor PER F. SKOOG GtfomegsPatented Nov. 16, 1948 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to the art of inlaying sheet material and, moreparticularly, is a method of patching veneer sheets by the removal lof amarred area and its replacement with patching stock, wherein the patchmay be adhesively held in place.

Hereinafter my invention is more fully described in accordance with itsapplication to the veneer and plywood industry by way of fullyexemplifying the method and the steps in its operation. It will beunderstood of course that this invention is applicable to manyindustries wherein it is desirable to inlay sheet material withnon-integral portions such, for example, as in producing decorativedesigns.

In the prior art, it is known to punch-cut sheet material and to placetherein patches which cccupy the space left by the displaced portion,usually a marred area. In my earlier Patent No. 2,336,703, entitledMethod of patching veneer sheets, and in Patent No. 2,336,704, entitledMeans for patching veneer sheets, I have taught a process, and amechanism for practicing that process, whereby a sheet is clamped aboutthe area to be punch-cut, the area is punch-cut, a plug is cut andinserted into the opening previously formed, all without the sheethaving been unclarnped and while maintaining the insert plug againstbuckling and edgewise expansion. In this process, it was earlier deemednecessary to include a step of disposing of the debris, removed from thesheet, prior to the cutting of a patch portion. The inclusion of thisstep necessarily required a time interval for such disposal. The methodalso included time in the operation for the placement of patching stockto be cut to the size and shape of the opening about to be lled. I havesince determined that not only can the operation be conducted moreexpeditiously, but that better results can be obtained by eliminatingthese steps during the main inlaying operation.

In my earlier process, the mechanism and the method did not includegluing the patching portion into the punch-cut opening, which isconsidered very desirable by the plywood industry for several reasons,among Which is the one that in facing sheet material it is desirablethat the line of joinder between the sheet and the patch therein besealed so that, subsequently, during the laying-up of plywood when theadhesive between the various plys is quite iiuid and the pressure isgreat, the normally darker colored adhesive will not be forced outthrough the joint and discolor the face of the exterior surface ply. Itis also desirable to seal the bers between the patch and the sheet atthe line of joinder so that subsequent exposure of the plywood tomoisture and weather conditions would not be marked by a raising of thegrain and a deterioration at the edge of the joint.

I do not intend to detract from the importance of the advantagesobtained by my earlier inventions because they are still fully usefulunder many conditions, including those wherein core stock is beingpatched and those Where surface stock is being patched and the objectionto discoloration or, grain raising is negligible.

Having in mind, however, the disadvantages of the prior art patchingmethods, it is an object of this invention to provide a process in theart of inlaying sheet material that may be practiced with greater speedthan has heretofore been possible.

Another object of my invention is to provide, in a process of the typedescribed, a series of steps which may include the sealing or adhesivejoining of the edges of the patch and the sheet material in which thepatch is placed without undue hand. labor or the employment of undulycomplicated mechanisms.

A still further and more specific object of my invention is theprovision, in a process of the type described, of the step of applyingan adhesive to the walls of the opening immediately in advance of andsimultaneously with the movement of the inlay member into the openingwithout adhesive having been previously applied to the patching member;and also to apply the adhesive in a brushing action for completedistribution.

Still another object of the invention is to include, in a process asmentioned above, the steps of disposing of the debris of thepunch-cutting operation and of positioning patching stock duringunclamped periods of the operation and to shorten the period requiredfor cutting the sheet material and placing the patch.

The foregoing objects and others ancillary thereto I prefer toaccomplish as follows:

According to a preferred embodiment of my invention, I patch veneersheets having a marred area by clamping the sheet around the marred areaand then punch-cutting the marred area from the sheet. Sequentially, byclamping an oversize piece of patching stock to the cut-out marred area,a patch is cut to the size and shape of the punch-cut opening in thesheet material. Next the patch is inserted into said opening, whilesimultaneously therewith and immediately in advance of the patch, anadhesive is spread upon the walls of the opening, followed by anunclamping of the sheet and the patch. During the unclamped period Iremove the cut-out portion and position, for the next cycle ofoperation, additional oversize patching stock for subsequent use. Theimportance of maintaining the sheet and the patch stock securely clampedfrom before initial cuttingr until after placement of the patch in theopening in the sheet is discussed in the patents mentioned above. Theinclusion of the glue-spreading step and the elimination of thedebris-disposing step during the actual inlaying operation, are realadvantages that are gained in accordance with this new method.

The novel steps that I consider characteristic of my invention are setforth with particularity in the appended claims. The invention itself,however, both as to its organization and its operation, together withadditional objects and advantages thereof, will best be understood fromthe following description of specific arrangements of steps, when readin connection with the accompany drawings, in which:

Fig. 1 is a view disclosing an arrangement of mechanism capable ofpracticing my method, which mechanism appears in th'e neutral position;

Fig. 2 is a view similar to Fig. 1 as the mechanism appears after thesheet material is punchcut and before the patching stock is cut;

Fig. 3 is an enlarged detail view of the operation of the insertion of apatch and showing the spreading of the glue in advance and simultane- Ai" ously with the movement of the patch; and

Fig. 4'is a perspective View of a fragment of patched veneer A patchingmethod useful in the art of inlaying sh'eet material and to overcome thedisadvantages hereinbefore encountered and enumerated above, must haveat least two totally distinct characteristics: it must be capable ofbeing performed in a shorter space of time than has previously beenpossible; and it must also produce inlaid pieces in sheet material whichpieces are securely held in place and the joints of which, with thesheet, may be sealed or adhesively joined and will not leak ordeteriorate in use. Accordingly, a preferred embodiment of my invention,referring to the figures of the drawing, is practicable by thc mechanismtherein disclosed.

The numerals I2 and I4 designate opposed frame members, or arms, thatare part of a larger bifurcated frame more fully disclosed in my LettersPatent No. 2,336,703, entitled "Method of patching veneer sheets, and No. 2,336,704, entitled Means for patching veneer sheets. Preferably, thearms are superpositioned and have, respectively, axially alignedpassages I3 and I5, in which are mounted the reciprocal punch-cuttingmeans and between which are passed the veneer sheets and the patchingstock during inlaying operations.

Within the opening or passage I3, is the reciprocally movable die I6,which carries the punch' I8 having cutting edge I9. A veneer sheet V ispunch-cut when the punch is moved through the aligned opening of backingmember 20. Punch I8 comprises a patch-shaped block having stem 2I which'is removably secured in a recess, provided in the ram I6, by means ofscrew 22. The cutting edge I9 is usually annular and has a taperinginner face forming a Wall of recess 23, in which the cut-out portion ofthe veneer sheet is retained when cut.

Recess 23 also encloses the anged head 24 of plug member 25. Theperiphery of head 24 is slightly undercut and lies in spaced apartrelation around the periphery with respect to the lower or bottom faceof cavity 23. In plug 25, in a suitable cavity provided therefor, isseated the ejector 26, pressed by spring 21, which is useful in ejectingfrom the cavity 23 a cut-out portion of a veneer sheet which may bedisposed therein.

During an inlaying operation, glue, adhesive, or sealing material issupplied to coupling 30 which is vertically movable with the ram I6 inslot 3|. Such glue passes from the coupling throughpassage 32 intopassage 33 in stem 2|, and thence to chamber 34 in the punch I8 underth'e plug 25. A plurality of passages 35 extend from chamber 34 toorices near the edge of the cupped recess 23 and under the periphery ofthe head 24. Glue is applied to coupling 30 from tank T by means of pump3'! that is periodically actuated by the cam 38 at a timed point in theinlaying sequence.

Because it is important that the veneer sheet V be clamped during theoperation of removing the cut-out portion, a die ram 40, reciprocallymounted in the passage I5, is provided to move into clamping positionagainst the back-up plate 2B and to clamp the Veneer sheet therebetween.The ram 40 is shaped as a hollow cylinder with side openings 4I, 4I,aligned to provide a passage therethrough. The lower face of ram 40comprises both a clamping member and a female die member shaped toaccommodate punch I8 and punch 48, the former working against the bottomand the latter against upper cutting edge 42. 4

By means of a pair of feed rolls 44 and 45, patching stock P is fed intothe die ram 40 through th'e openings 4I, 4I, in order to position thepatching stock relative the cutting edge 42 for the cutting of asuitable insert or inlay plug member.

Patching strip P is cut to form an inlay mem- -ber I by means of theinlay punch 47, which is carried on th'e lower end of the reciprocalpunch ram 48. The inlay punch contacts, in its descending travel, theupper face of strip P and forces a portion of the same downward againstthe cutting edge 42 and thence through passage 43 and into the veneersheet, as will be more` fully described hereinafter.

The steps of the operation are sequentially il lustrated in Figures 1,Zand 3. In Fig. 1, the mechanism is shown in the neutral position, withthe veneer sheet, as well as the strip P, un-4 clamped. Both rams I6 and48 are in the retracted positions. In Fig. 2, the punch' I8 has beenmoved upward through the veneer sheet V and has had cut therefromportion D, constituting the debris of the operation. Portion D lies incavity 23 and, with the backing head 24, lls.

cavity 23 to provide a flush backing against the strip P when the patchor inlay is cut upon a downward stroke of ram 48 and punch 41 past edge42, and Whilethe. same ispassed through opening `43 of die ram Ml.

Theedge of portion D, as appears in the enlargedshowing of Fig. 3, hasbeen slightly tapered or compressed by means of the inner sloping faceof recess 23. Cut-out D'rests upon head 24 in close juxtaposition. Bythis arrangement, it is to be noted, during the cutting of the veneersheet, the same is clamped between members 2U and 40, and also the patchor insert I, after cutting, is at all times clamped between debris D andthe male punch M.

In Fig. 3, the insert I is shown as about to move into the openingformed in sheet V. As this occurs, pump 3l is actuated by cam 38 and asmall, measured amount of the uid is forced through passages 32 and 33,chamber 3d, and into the passages 35, to be discharged, under pressure,to immediately below the edge of head 24. The glue escapes between thesloping wall of the recess 23, and the edge of the debris D and is wipedin a spreading action upon the wall of the previously formed opening inthe sheet V. This application of adhesive or sealing material to theopening being inlaid is accomplished simultaneously with the insertionof the inlay and immediately in advance thereof, as the same moves intothe opening. Since the fibres at the edge of the debris portion D tendto drag over the edge i9 of punch i8, they act as a brush and sweep overthe wall of the sheet opening in a manner to assist distribution of theadhesive and to force the same into the cavities of the wood walls.Since the glue is under pressure during the inserting period, it willtend to ow into any cavities within its path, but the brushing actionserves also to restore the nbre structure in the wall of the openingmore or less to normal.

It is to be noted that the fibres in the opening wall are usually bentby the lower cutter during the punch-cutting of the sheet V, and thatthey will be bent oppositely by the insertion of the plug as it isforced into the opening. Under such conditions, the bres of the inlayplug and of the sheet tend to interlock. In the presence of theadhesive, a secure and sealed joint will be formed. This joint hasconsiderable strength, and produces perfect mating or alignment of theoutside faces of the inlay and the sheet. During the insertion of theinlay plug I, even though there is glue being applied to the walls ofthe opening, the periphery of the debris portion D serves to protect theinlay from being smeared with glue, since D has an upper dimension thatis the same as the inlay, because the two are cut to exactly the samedimensions on mating die elements.

When the inlay I is properly placed in sheet V, the ram i5 is caused toretract downward and ram 48 will be similarly retracted upward, in theopposite direction. The pressure is thus removed from portion D, thespring pressed ejector 26 acts to shove the debris out of recess 23. Ablast of air passing through conduit 5U into the space above the punchI8 picks up the debris and blows it out through opening 5|.

With the ram retracted to approximately the position shown in Fig. 1,the rolls 44 and 45 are rotated to feed forward an additional portion ofthe strip P for subsequent cutting of another inlay plug or patch duringthe next inlay sequence. It is also during this portion of the cyclethat the operator shifts the sheet material for the next inlaying orpatching operation.

The movement of the various rams, dies, and

clamping members, as well as the injection of glue, the operation of theair blast to remove the debris, and the indexing forward of the veneerstrip P, are all accomplished by suitably timed operating mechanisms, asis more clearly disclosed in the Letters Patent mentioned above.

It is preferable in the operation of the method herein described toemploy a glue, ller, or sealer material, which is preferably uncolored,and which will serve to seal the joint as well as to cause the inlay toadhere in the opening in which it is placed in the sheet material.

This method is particularly applicable to the treatment of external plysof sheet material, since the ordinary blood-colored glues employed inthe adhesive industry may be safely applied between the inlaid facingsheet and the adjacent core layer, and the whole may be bonded togetherwith the usual high pressure and heat customary in the industry, whilenone of this colored adhesive, interior of the sheet, will be forcedthrough the sealed joint between the patch and the opening. Thus isavoided discoloration of the face of the sheet, which would otherwise beunsightly and tend to down-grade the finished plywood. There is anotherimportant reason for adhesively joining or sealing the inlay into thesheet, and that is that the bonding agent serves to prevent the ends ofthe bres from raising in the joint between the inlay and the sheet afterit has been exposed for some time to the weather.

In Fig. 4, the fragment of veneer sheet V is shown with patch P in placefollowing the cornpletien of the operation depicted as beginning in Fig.3 and with the clamping pressures released. In this instance, the patchis shown as a boatshaped patch, conventional in the plywood industry,because of its ability to blend with the grain of the main sheet.However, from a mechanical standpoint, I have found it desirable,although not necessary, to blunt the ends of the patch to provide easyfitting of the patch to the veneer and to avoid sharp pointed dies.

While I have shown and described particular embodiments of my invention,it will occur to those skilled in the art that Various changes andmodifications may be made without departing from the invention, and Itherefore aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of my invention,

I-Iaving thus described my invention, I claim:

l. In the art of patching veneer, the method, comprising: perforatingsaid veneer at the point to be patched to provide an opening havingwalls perpendicular to the faces of said veneer, unidirectionally wipinga coating of adhesive under substantial pressure on the walls of saidopening in a motion withdrawing from one edge of the opening to theother, simultaneously therewith inserting a patch piece equal in sizeand shape to said opening thereinto by causing the same to move andfollow in the same direction the wiping application of the adhesivecoating in immediate sequence, and terminating said movement of thepatch piece when the same is in substantial alignment with at least oneface of the sheet material surrounding said opening. Y

2. In the art of setting a pre-formed inlay member into a similar sizedopening through sheet material, the method, comprising: unidirectionallywiping a coating of adhesive under substantial pressure on the walls ofsaid opening in a motion withdrawing from one edge of the opening to theother, simultaneously therewith insert-` 7 ing the inlay piece into theopening by causing UNITED STATES PATENTS the same to move and follow inthe same direction the wiping application of the adhesive Coating inNflgfgefw Maggi De?? 1934 immediate sequence, and terminating said move-2336704 Skoog Dec 4 1943 ment of the inlay piece when the same is insub- 5 stantial alignment with at least one face of the FOREIGN PATENTSsheet material surrounding said opening. Number Country Date PER FSKOOG- 648,111 France Aug 7, 1923 REFERENCES CITED 10 635'699 GermanySelm 25 1936 The following references are of record in the le of thispatent:

